JPS5854580A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that heats an object to be heated, such as food, using high-frequency energy.

In particular, this invention relates to an improvement in the radio wave leakage prevention mechanism provided at the door periphery.

Conventionally, as a means to prevent the leakage of the fundamental wave and the second harmonic component of the heating frequency (e.g. 2,450 MHz), a method was proposed in Japanese Utility Model Publication No. 49-31807 in which grooves were provided to the depth of the fundamental wave leakage. However, in this case, both grooves are provided at different positions, and the structure is complicated, which does not meet the following requirements.

In other words, IC! , microcomputers and other small, multi-functional electronic components have been incorporated into the control circuits of high-frequency heating equipment, simplifying the operation panels and making them thinner and more efficient. There is a demand for thin doors that can be removed.

Therefore, in the present invention, the choke groove for the fundamental wave and the choke groove for the second harmonic are made to face each other in opposite directions, and a radio wave attenuation cavity with one entrance is provided. The purpose is to provide a heating device.

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an external view showing an example of the high frequency heating device of the present invention. 1 is an outer box, 2 is a door, and 6 is an operation panel with a thickness that is balanced with the thickness of the door 2.

The operation panel 3 can be changed in various ways depending on the purpose.
The case of automatic heating will be explained as an example. 4 is a display device that shows high frequency output, remaining heating time, etc.

5 is a menu selection button that determines the optimal heating pattern for each menu, 6 is a finishing adjustment knob that allows you to select the degree of finishing according to your preference, 7 is a heating button to press to start heating, and 8 is for opening the door. This is the door open button.

FIG. 2 is a schematic cross-sectional view of the main part of the high-frequency heating device corresponding to FIG. 1. 9 is a high frequency oscillator that generates high frequency energy, and 10 is a waveguide for transmitting the high frequency energy from the high frequency oscillator 9 to the heating chamber 11. 12 is a turntable for uniform heating, on which the object to be heated is placed. A turntable 12 is used as a uniform heating device.
In addition, a star 2° rotating antenna, a fixed antenna, etc. may be used. Reference numeral 13 denotes a transparent plate attached to the front surface of the door 2, and the transparent plate 13 is fixed to the door front plate 15 by a door cover 14. A door rear plate 16 is attached to the door front plate 15 with screws 17. Both the door front plate 15 and the door rear plate 16 are made of metal plates.
Radio wave attenuation cavity 1 facing opening periphery 18 of heating chamber 11
form 9. 2D is a transparent plate facing heating chamber 1HC,
1 is a wire mesh (or perforated metal plate). Transparent plate 13
．． The inside of the heating chamber 11 can be seen through the wire mesh 21 and the transparent plate 2o. 22 is a sash that surrounds the door 2.

FIG. 6 is an enlarged sectional view of the vicinity of the radio wave attenuation cavity 19 shown in FIG. 2. Heating frequency e.g. 2,450~flz
A choke groove 19a for the fundamental wave to prevent radio wave leakage to the frequency 4.9 [10 Mll
One radio wave attenuation cavity 19 having one entrance 23 is formed by opposing the second harmonic grooves 19'b in opposite directions to prevent radio wave leakage to xK. In the fundamental wave choke groove 19a, the L-shaped radio wave propagation path (thick arrow) from the inlet 26 to the short-circuit surface 15a is set to approximately τ with respect to the free space wavelength λ of the heating frequency. The fundamental wave choke groove 19a is connected to the heating chamber 1.
1, and one wall surface 16a of this groove 19a is used as a contact surface with the peripheral edge 18 of the opening of the heating chamber.

Furthermore, in the second harmonic channel groove 19b, the L-shaped radio wave propagation path λ (bold arrow) from the inlet 26 to the short-circuit surface isb is approximately ■.

As described above, according to the present invention, as shown in FIG.
The choke groove for the fundamental wave and the choke groove for the second harmonic are opposed to each other in opposite directions, and the radio wave propagation path length in each choke groove is determined by appropriately adjusting the length in the direction parallel to the periphery of the opening of the heating chamber. To provide a high-frequency heating device that can obtain the necessary dimensions by selecting the desired size, and can be finished with a desired appearance in terms of a balanced design of an electronically thin operation panel since the door thickness can be thin. be able to.

[Brief explanation of the drawing]

FIG. 1 is an external view showing an embodiment of the high-frequency heating device of the present invention, FIG. 2 is a schematic sectional view of essential parts showing an embodiment of the high-frequency heating device of the present invention corresponding to FIG. 1, and FIG. 3 is an enlarged view of the vicinity of the radio wave attenuation cavity 19 in FIG. 2. FIG. 2...door, 11...heating chamber. 18... Heating chamber opening periphery, 19... Radio wave attenuation cavity. 19a...Fundamental wave choke groove. 19b... Chiyoke groove for second harmonic. 23... (Radio wave attenuation cavity 19) entrance. Applicant: Hitachi Thermal Appliances Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A choke groove for the fundamental wave (19a) and a choke groove for the second harmonic (
19b) are opposed in opposite directions to constitute a radio wave attenuation cavity α9 having one inlet.